| Author(s) | Ahmad Al-Saleh |
| Affiliation | Geology Department, King Saud University, Riyadh, Saudi Arabia |
| Title | Metamorphic History of Gabbroic Blocks within the Ar Ridayniyah Ophiolitic Melange, Eastern Arabian Shield, Saudi Arabia |
| Source | Journal of King Saud University. Science. Volume 15, No 2. (2003/1423) |
| Abstract | Abstract. The Al-Amar suture marks the collisional boundary between the Afif and Ar Rayn terranes of the eastern Arabian Shield. Numerous ophiolite occurrences are reported from this suture; many of which are made up of a serpentinite melange that encloses blocks of varying oceanic lithologies. The Ar Ridayniyah melange is exposed in a narrow linear belt near the eastern periphery of the suture. Most of the blocks are massive serpentinites with some gabbros and rare basalts, all of which are set in a matrix of highly sheared serpentinite. The gabbros contain secondary assemblages indicative of two phases of metamorphism; the first is an ocean-floor event, but the second is a medium-pressure short-lived episode that reached up to epidote-amphibolite conditions. It is believed that this second phase is the product of the final collisional event between the two enclosing terranes which took place at c. 610 Ma. |
